1. Field of the Invention
This invention pertains to workpiece-positioning apparatus, particularly of the type designed for moving elongated structural members, such as channels, I-bars or the like, to an accurately located position beneath a punch or similar tool. The invention also pertains to a workpiece clamp that is particularly useful for allowing removal of the workpieces from above the clamp. The invention also pertains to a unique rotary-to-reciprocating drive for moving elongated structural members.
2. Description of the Prior Art
Heretofore, ironworkers, in particular, have been provided with workpiece-support tables that require the manual movement of the workpiece. Lateral movement of the workpiece has generally been done by a manually propelled crank which shifts a portion of the work table laterally toward and away from the punching station of the ironworker. Longitudinal movement of the workpiece has generally been done manually by grasping the workpiece and pushing it along a table. The manual manipulation of workpieces on the table is time-consuming and requires the judgment of the operator to determine the exact location on the workpiece for performing the punching, notching or suitable operation on the workpiece.
Workpiece clamps have heretofore been provided with an upper part which is rotatable in a horizontal plane to allow the placement of a workpiece on the lower part of the clamp. Such work clamps have not operated effectively in some cases due to the difficulty in having to provide both a rotational force and a clamping force on the upper clamp member.